Chemistry · No topic
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Which element has smallest ionic radius?
- A
Li+1
- B
Na+1
- C
K+1
- D
Rb+1
The correct answer is Li+1 because it is the smallest cation among the options listed. Ionic radius generally decreases as you move from left to right across a period due to increasing nuclear charge, which pulls electrons closer to the nucleus. Since Li+1 has the least number of electron shells (only two), it has the smallest ionic radius. In contrast, Na+1, K+1, and Rb+1 each have additional electron shells, which increases their ionic radii. Therefore, they are larger than Li+1.
Li+1 has the smallest ionic radius among the provided options because it has the least number of electron shells, resulting in a stronger effective nuclear charge that pulls the electrons closer to the nucleus.
Na+1 has a larger ionic radius than Li+1 because it has one more electron shell, which increases the distance between the nucleus and the outermost electrons.
K+1 has an even larger ionic radius than Na+1 due to having two additional electron shells, leading to a larger ionic size.
Rb+1 has the largest ionic radius among the options provided, as it has three additional electron shells compared to Li+1, resulting in a much larger size.
Tagged under Chemistry · No topic · 2025